Optical communication systems are presently being developed which include a light source, a light detector and an optical fiber connected between the light source and the detector. In such systems, electroluminescent semiconductor diodes, such as laser diodes and light emitting diodes, are used as the light source. To connect the optical fiber to the electroluminescent diode so that the light from the diode enters the optical fiber, it is necessary to align the optical fiber with the surface of the electroluminescent diode from which the light is emitted. Similarly, it is necessary to align the optical fiber with the photosensitive surface of the light detector.
In the prior art, for example, the diode and the optical fiber typically are each mounted on separate mounting blocks. After the end of the optical fiber is aligned with the light emitting surface of the diode by moving the two mounting blocks relative to each other, the mounting blocks are secured together with a suitable cement, generally a resin cement which is then cured, to hold the optical fiber in alignment with the diode.
In one technique described in U.S. Pat. No. 4,237,474, incorporated herein by reference, an electroluminescent semiconductor diode assembly includes an electroluminescent semiconductor diode mounted on a mounting block, and an optical fiber mounted on a securing block with an end of the optical fiber being adjacent to and aligned with a light emitting end surface of the diode. The securing block can be moved both vertically and horizontally to permit alignment with the diode. The two mounting blocks are secured together through at least one thin layer of cement. The cement layer is thin enough to minimize relative movement between the mounting blocks when the cement is cured but thick enough to permit ease of movement between the mounting blocks prior to curing the cement. Unfortunately while the cement is curing it is necessary to maintain the fiber in the correct position a problem that is complicated by the need to permit vertical movement of the securing block for purposes of alignment.